It’s that time of year again. ‘Tis the season for ugly Christmas sweaters, hot chocolate and the flu. 

That’s right—the holiday season is synonymous with fevers, coughs and sore throats. To make sure you’re passing the pumpkin pie instead of the Kleenex box this year, we talked to Dr. Janko Nikolich-Zugich, head of the UA Department of Immunobiology, about the importance of flu vaccinations. 

DW: What is the flu virus?

The flu virus is a small, unique virus with its genetic material chopped up into nine different segments. The flu virus itself can infect both human and animal hosts—that’s where you get things such as the bird flu or swine flu. 

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If two different flu viruses infect the same host, the viruses will readily exchange their genetic material. That means the virus that comes out will potentially be different than either of the two that came in. 

Why does the flu require annual vaccinations, unlike other viruses?

The main reason is the variability of the virus. Many other viruses and bacteria do not change that much, and so you can vaccinate once in a lifetime and then take a booster shot 10 years later. With the flu, it’s a different story because the virus varies so much.

What’s in a flu vaccination?

What you get in a shot is basically a vaccine cocktail of three different flu viruses. They are all dead, which means they are inactivated and cannot make you sick or replicate.

How does the vaccination work to fight off the flu?

The vaccination is trying to trick your immune system into thinking there is an infection, even though the virus cannot multiply. Our immune systems—particularly our white blood cells—protect us against any infection that might arise. Our immune system is highly flexible. We have a huge army of very diverse white blood cells called lymphocytes, which will ultimately deal with an infection like the flu.

We have a few thousand cells that are specific for each different virus. Once the flu virus gets into your body, it’s going to rapidly multiply, entering your cells and turning them into virus-producing machinery. To catch up with this rapidly multiplying virus, our lymphocytes also multiply very quickly, getting armed and dangerous as they do so they can destroy the virus. It takes between four to six days for these cells to multiply to the point where they are effective killers. 

What happens to your lymphocytes once they’ve eradicated the flu?

Once you eliminate the infection, you don’t need billions of cells that are specific for a virus that is no longer in you. Most of your cells will die by programmed cell death. However, a larger army of them will stay with you, known as memory cells. These cells have already seen and recognized their virus, so they can protect you from the next infection of the same type.

Why do we get the flu around the same time every year?

Temperature patterns increase the likelihood of new flu strains hitting a given area at a particular time of year. As the weather gets colder in the U.S. from late August to September, the chances for the survival of the flu virus increase. The fact that we go indoors and get closer to one another during the colder months also contributes to the spread of flu virus.

One reason why flu virus is so successful is it can spread quickly and easily by sneezing and coughing.

Which factors make people susceptible?

The main things that erode your immunity are poor nutrition and lack of sleep. The other part that helps is moderate-level exercise, which keeps your immune system going. Strenuous-level exercise can have a detrimental effect. In regards to nutrition, the diversity of your diet is what matters. 

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A large amount of vegetables will give you all the minerals and micronutrients which are critical for the functioning of the immune system. Fighting off the flu is a very energy-dependent process, so you need to have sufficient energy and enough building-block material for your cells to multiply into thousands of virus-fighting antibodies. 

Are there any negative sides to vaccinations?

Some people may have allergic reactions, especially if they have egg allergies. In that case, there are egg-free versions of the vaccine.

The famous case of autism and vaccinations is also untrue. There’s absolutely no evidence whatsoever that autism is in any way linked to them. Vaccines are exceptionally safe and have been successful in eradicating deadly diseases such as smallpox.

What would you say to students wondering if they should get a flu vaccine this year?

Vaccinations are a great idea. In the student population, the efficacy of the flu vaccine is very good and very strong. People who are vaccinated either don’t get the flu at all or get a much milder version.

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